In 2006, the ITU-R (ITU-Radiocommunication Sector, ITU-Radiocommunication sector) officially named B3G (Beyond 3G, Beyond 3G) technology as IMT-Advanced (International Mobile Telecommunications-Advanced, international mobile telecommunications-advanced) technology. In one aspect, the IMT-Advanced has a high requirement on system capacity. In another aspect, a high bandwidth spectrum that can support such huge capacity generally can only be found in a high frequency band. Path loss and penetration loss of such a high frequency band are relatively large, and it is hard to implement a good coverage. To meet the capacity requirement of the IMT-Advanced, a LTE-Advanced system proposed by the 3GPP (3rd Generation Mobile Group, 3rd generation mobile group) takes the relay technology as one of candidate technologies for improving the system capacity and coverage.
In a traditional network, wireless connection between an eNodeB (eNodeB, eNB) and a user equipment (User Equipment, UE) is a direct wireless connection, that is, a single-hop network. However, in the relay technology, one or multiple relays (Relay) are added between the eNodeB and the user equipment, responsible for forwarding a wireless signal sent by the eNodeB to the user equipment. One eNodeB may service multiple cells, and different cells are sorted into different TAs (Tracking Areas, tracking areas) according to certain rules. The user equipment, each time moving to a new TA, initiates a location update request to a network side, reporting its latest location information to the network side. A MME (Mobility Management Entity, mobility management entity) maintains a TA list for each user equipment according to the location information reported by the user equipment. Each time the network side pages a user equipment, and the MME searches out all eNodeBs associated with the TAs according to the current TA list of the user equipment, and sends a paging message to these eNodeBs.
In one aspect, the eNodeB does not acquire the TA information about its relays, and cannot acquire whether the paged user equipment camps on a cell of the eNodeB or a cell of its relays. Therefore, the eNodeB, when starting paging the cell of the eNodeB, sends the paging message to all its relays so that the relays start to page the specified user equipment.
Therefore, during the implementation of the present invention, the inventor finds that the prior art has the following problem.
To page a specified user equipment, paging needs to be performed in the cells of the eNodeB and cells of all relays of the eNodeB, which increases signaling overhead of system paging and wastes system paging resources. For the eNodeB, because the relay needs to allocate its paging resources to two wireless links from the user equipment to the relay and from the relay to the eNodeB, the relay has insufficient resources as compared against the eNodeB. Therefore, the problem of a waste of the paging resources becomes more severe.
In another aspect, when the relay moves to a cell of the eNodeB for the first time, the eNodeB broadcasts a system message in the tracking area to which the cell belongs. The relay forwards the system message to all user equipments camping on its cells. These user equipments are loaded into the cell of the eNodeB inside the relay, so generally these user equipments access the tracking area of the eNodeB for the first time. Therefore, according to the current protocol, all the user equipments of the relay undergo a location update.
Therefore, during the implementation of the present invention, the inventor finds that the prior art has further the following problem.
A great number of user equipments may exist in one mobile relay, and all the user equipments need to undergo a location update concurrently, causing great signaling load to the air interface in a short time, and hence affects normal voice and data communication. The mobile relay may be in a high-speed motion, and therefore, it may enter the coverage of a cell of another eNodeB in a short time. However, a great number of the user equipments undergo the location update concurrently and repeatedly, thereby causing heavy singling load.